Hydraulic control



' Nov. 16, 1943. R. F; CARR ETAL HYDRAULIC CONTROL Filed'Aug. Q, 1941 5 Sheets-Sheet l la) 3 MIQMMATTORVNEYQS Nov. 16, 1943. R. F. CARR ETAL 2,334,383

HYDRAULIQ CONTROL Filed Aug. 4, 1941 s Sheets-Sheet 2 7/ .il nlll M 45 'INVENTOR w PAYMOHD E (A El? E/rem: C. BOHHLL 4 ATTORNEY HYDRAULIC CONTROL R. F. CARR ET AL 2,3343% 5 Sheets-Sheet 3 Filed Aug. 4, 1941 ,4/ I a 22:22:24. 2:12:11. 4 W321i ATTORNEY 'of the above kind is dependent, among, other has. re. i 3

panes are tinieserrios masonic ooNraoL i Raymond F. Carr and Earle 0. 301112111, Seattie. Wash, assignors oi one-third to R Bohall, Seattle, Wash.

' Application Alilgiilst 4, ran, Serial No. stress 4 ohms. 'i'oi; sir-sac)- This invention relates to hydraulic power transmission means and remote control systems. More particularly, the invention has reference to improvements in closed, hydraulic control systems sometimes referred to as puisator systems,,. characterized by having a transmitter piston or plunger operable in one cylinder of the closed hydraulic system to eifect, through the mediacy of a confined hydraulic medium, an instant and corresponding movement of a piston or plunger in a receiver cylinder, which might be located at instant and corresponding movement of the piston of the other or receiver cylinder for the functional actuation of a mechanism operating under control of the present system; r

Explanatory to the present invention, it will bestated here that the maximum efiectiveness, emciency and positiveness of a system of control things, on maintaining the closed or torque transmitting portion of the system free of air, or vacuum and completely filled with the operating hydraulic medium under super-atmospheric pressure.

It will be mentioned also, as explanatory to the invention, that leakage oithe hydraulic pressure medium from the system is not always or only past the valves, piston packing,' or other movable parts or loose connections between parts which confine the hydraulic medium, but freouently is the result of seepage through the pores of the metal pipes, housings and other parts in which the oil, or. whatever hydraulic medium is used, is confined. It is a fact, also,

' that whenever leakage of this character, referred to as .weeping, doesoccur, even though it be measured in drops, it is essential that the loss Toe-compensated for, or otherwise it will cause'thev system to lose its necessary positiveness of action so and its timing 'or adjustment, without yvhiclrit becomes unsatisfactory in use, if not inoperative.

- 'In view of the above explanatory remarks, it has been the principal object of this invention to provide certain improvements in systems of this kind whereby any loss of hydraulic medium from the system that may occur from weeping" or leakage incident to normal use of the device, will be automaticall replaced. Furthermore, to

5 provide a means for the replacement of leakage in a manner whereby a super-atmospheric pressure will be maintained at all times on the hy-- draulic medium confined in the system. 7

More specifically stated, it is the object of this to invention to provide a system of the character above referred to wherein a pump of novel kind is operable to maintain a. definite hydrostatic pressure on a stored supply of hydraulic medium, and thlspressure will operate to efiect the forced it feed of medium from the supply as and when needed for replenishing or for compensating for any leakage that may occur in the closed system. Other objects of the invention are to be found in the details of construction and arrangement of 20 parts embodied in the pump, and in its means for and mode oi operation, together with novel features employed in the various adaptations and modifications or the present type of equipment.

In accomplishing these and other objects of 21s the invention, we have provided the improved details of construction, the preferred forms e or which are illustrated in the accompanying drawings, wherein- I Fig. l is a view illustrating a. hydraulic remote 8d control system of the dual transmitter type in which the present invention is embodied.

Fig. 2-ls an enlarged, longitudinal section of one of the transmitter cylinders and its contained parts, taken substantially on the line 22 in as Fig. 3. Y

Fig. 3 is an irregularly taken, horizontal'section of a transmitter cylinder, taken substantielly on the line 3-8 in Fig. 2.

Fig. 4 is a cross section of the transmitter cyl-.

so, inder substantially on-line 6-4 in Fig. 3.

Fig. 5 is an enlarged, longitudinal section of V the pressure retaining pump.

mg. as is a longitudinal section'of the receiving cylinder and its enclosed piston.

@535 o Fig. '7 is a sectional detailof a transmitter pis' ton and pumpof an alternative form.

Fig. 8 a .a sectional view of a 0.? alternative construction.a Referring more in detailto thedrawings- First, it is to be understood that the present type ofsystem is applicable to many uses and to many different adaptations, but most generally is employed for the control of movable parts or I instrumentalties located .in' places dificult. to

se reach.- For example,-such systems are especial v receiver piston ly suited for the remote control of steering gear in boats, for actuation of engine throttle levers or reverse gear levers below closed hatches, or for the shifting or moving of doors, windows or the like, from a remote station of control and for many analogous uses where the transmission of power through practically a frictionless medium is desirable or advantageous. present drawings, we have not illustrated any particular mechanism under control, but have only shown the transmitting and receiving instrumentalties in which the present improved features are embodied and indicated a part that is operated by the receiver cylinder.

It is to be understood that the device, in the forms shown, or in modified forms of connection, might be adapted to various uses without any departure from the spirit of the invention. Therefore, these illustrations are to be considered as typical of many uses.

Referring first to Figs. 1 to 4:

In the system as here shown in Fig. l, I designates, in general, what will hereinafter be referred to as the transmitter cylinder, and 2 des- ;,ignates, in-general, what will be referred to as the receiver cylinder.

In the transmitter cylinder, a double acting piston 3 is fitted for reciprocal action; this being shown in detail in Fig. 2. Likewise, in receiver cylinder 2, there is fitted a double acting piston 4 which may be of the same general type of construction as piston 3. Closed pipes 5 and 6, respectively, connect the opposite ends of the cylinder I with the opposite ends of cylinder 2,

' and, as illustrated in Fig. 1, it is possible to so arrange these pipe connections that movement of In the In Fig.1, we have illustrated a dual control for the receiver cylinder in that a second transmitter cylinder, IA, is provided and is connected transmitter cylinder, I or IA, provided that, when a selected transmitter cylinder is in use, the other is locked, or secured in a neutral position. Therefore, the following description, insofar as it pertains tothe transmitter cylinder I and its associated parts, will be considered to apply equally to transmitter cylinder IA and its associated mechanisms.

By reference-to Fig. 2, in particular, it will be understood thatthe transmitter cylinder I comprises a central housing section Ia, with opposite end housings Ib and I0, fitted thereto and all held in assembled relationship by connecting bolts 8. The parts Ib and I0 are formed with cylindrical body portions. These are arranged in axial alinement and contain therein, respectively, the opposite end portions of the piston 3 for reciprocal action. The outer ends of these cylindrical portions are closed by integral end walls into which the ends of the connecting pipes 5 and 6 are extended and secured by the fittings 9.

The central housing Ia is'formed with a relatively large closed chamber I2 into which the inner ends of the cylindrical housings lb and Ic open, and which surrounds the medial portion of the piston 3. Rotatably mounted in the upper portion of the housing Ia and within chamber I2, and extending transversely of and above the piston 3, is the transmitter shaft I3 on which a gear segment I4 is fixed. The teeth of this segment are arranged to operatively mesh with the teeth of a rack I5 formed along the top side of the medial portion of the piston 3. It will readily be understood that with this arrangement of parts, rotation of shaft I3 and gear segment I4 in opposite directions, will cause reciprocal action of the piston 3 in opposite directions in its cylinder, and incident to such action,

the piston 4 of the cylinder 2 will be actuated accordingly under the influence of the hydraulic medium with which the system is filled.

The shaft I3 extends to the outside of the housing Ia through a side cover plate I j which may be removed for access to the interior of the cylinder.

It is immaterial by what means or devices the shaft I3 is rotated for the actuation of the transmitter shaft and piston. The shaft maybe, and in many cases is, equipped at its outer end with a hand lever. In Fig. 1, we have indicated the transmitter shaft as being equipped with a gear segment I6 operated by a gear I6, fixed on the mounting shaft I! of a hand wheel I8. The kind of control lever generally would be determined by choice of construction or in View of the character or use of the particular system with which this device is employed.

It is to be understood that each of the pistons 3 and! should be equipped with suitable packing at its ends to prevent, to the maximum extent possible, any possible leakage past the piston. In the present instance, we have illustrated, at I9, a certain type of "chevron packing found to be the most satisfactory, but we do not wish to be confined in any way to any particular kind, or type of packing. I

In the present equipment, the housing Ia and chamber I2 serve as a storage receptacle in which a supply of liquid medium may be confined under hydrostatic pressure and from which smallamounts may be automatically released, as will presently be explained, to the system to replace or compensate for any amounts that leak from the system.

By reference now to Figs. 2 and 3, in particular, it will be observed that the housing section lb of the transmitter cylinder is'formed along one side with a longitudinally directed-channel 25 which,

at its inner end, communicates with a port 26 in the adjacent end wall of housing I a and which opens into the upper portion of chamber I2. At its outer end, this channel 25 communicates with a channel 21 that is directed transversely of the cylindrical body and which opens into the outer end of the cylinder I at its top side. Located in the channel 21 is a back check valve 28, as seen best in Fig. 3, urged to closing position against a seat 29 by a coiled spring 30; the disposition of this check valve being such that it will operate to retain the liquid medium under pressure in the cylinder, but will open whenthere is a greater pressure at the outside of the valve than in the cylinder resulting from leaking from the cylinder or piping system.

It will also be observed by reference to Figs. 2 and 3, that the housing section Ic, likewise is formed along one side with a longitudinal chan- I assases nel 3! which, at its inner end. registers with a port 32 in the adjacent end wall of the housing m and opening into chamber l2. At its outer end, this channel 3| opens into a transversely directed channel 33 which, at its inner and communicates with the adjacent outer end of the cylinder l.

Likewise, in the channel 33, is a back check ball valve 34 urged to-closed position against a seat 35 by a coil spring 38 and this valve operates to retain pressure in that end of the cylinder, but will open to admit medium to the cylinder when pressure inside the cylinder is less than that at the outside of the valve due to leakage from the cylinder or the pipe connections of the system.

In order that the ball check valves 28 and 3! maybe manually moved to and then held in open position, as is'desired when charging the system with a hydraulic medium, there .is provided at the outer ends of the transverse channels 21 and it, closing fittings 31 through each of which a stem 38 is threaded. The inner end ,ofeach stem is adapted to be extended into its corresponding channel beyond the valve seat to engage and unseat the ball valve thus to provide for free flow of medium through the channel. For turning the stems. 38, each has a handle member 39 at its outer end. Y

As was previously explained, unavoidable leakage occurs in systems such as that above discussed, and thus, in accordance with the objects of this invention, we have provided means for the automatic replenishing of oil that may leak from the system. Our preferr d means comprises, the following:

As will be observed best in Figs. 2 and -5, there" is a chamber d0, set ofl in the top side of the cylinder housing.'located partly inthe housing la and partly in housing section lc. This chamber is'entirely separated from the chamber I! by a partition wall 42 shown in Figs. 2 and 3.

42, providing for communication betweenfchamhere It and Hand this passage, as observed in Fig. 3, is equipped with a pressure relief valve 85 that may be regulated to open at any predetermined pressure for flow of oil from chamber I2 into chamber 40 through passage 84.

Now assuming the parts to be so constructed I and assembled, it will be understood that incident to oscillation of the actuating lever for shaft It for actuation of the transmitter piston I in Y either direction,the cam 46 will impart a pumping action to the piston 45 and this will effect the pumping of oil from storage chamber 40 intov chamber I2 against the head of trapped air, time to build up and maintain the supply of oil in "opposite en,ds of the cylinder I.

, Now, assuming that leakage should occur that would reduce the pressure of oil in the cylinders tor}, or in the piping system connecting the cylinders, or at any other point in the system that might affect the' positiveness of operation, a

or change in piston timing, such leakage would reduce the hydrostatic pressure in the affected parts of the system and there would be an automatic opening of the valve 28'or 34 forreplenishing this loss from chamber I 2.

It will be understood also that the, pumping action imparted to the piston 45 incident to nor- Mounted i the wall; 42, parallel .with the axis. of the cylinder 9 is a small pump cylinder 43 formed with a piston "chamber 44' in which a, pump pistonli is-reciprocably contained. The

cylinder 43 opens at one end through the wall 42 into chamber l2, and the piston 45 extends through and beyond that open end into the' chamber 12- and there has a rounded ,outer end portion 45a engaged with a cam Ml that is fixed on the shaft It, The cam has rises 48' and 46a diverging voutwardly, and the pump piston 45 has 'itsrounded end engaged with the cam surface so that on rotating the shaft l3- in either direction from a neutral position, the cam will actuate the piston outwardly in its chamber The outer'end of pump cylinder 43 has a chan-. nel. 48 opening from chamber into chamber and in this channel is a back check ball valve I! urged against its seat ll (by a coiled'spring 5i.

'I'his-valve.closes under back pressure that is created in passage 48 incidentto outward travel of piston under influence of'cam 48. Also,

mal use of the system, will operate to maintain the medium in chamber l2 under super-atmospheric pressure at all times and this pressure will be maintained in the piping system, insuring that at no time will there be'air; allowed to enter the system due to the super-atmospheric pressure maintained on thehydrauhc medium which fills and supplies the system.

" i In order that at no time will there'be any shortage of-llquid for replenishing the system, we have provided a connection 10 leading from a source ofsupply of liquid designated at H and opening, into the top of chamber 40. Thus.

chamber 40 may be kept full at all timesby gravity flow from the source of supply.

Now referring to the receiver cylinder 2: This preferably would be constructed substantially- 'in accordance with the cylinder l, except that the chamber #0 and pump 'mechanism of the transmitter cylinder would be omitted. The pisthere is a longitudinal channel 54 in the piston 46 opening at its opposite ends-intothe piston chamber M and through the outer end portion of the piston into'the chamber l2. In this channel is a -backcheck' ball valve urged towardits seat 6| bya' spring 82. Thisvalve and seat are so arranged that the valve may be forced 'open by pressure of liquid, confined in chamber M when the piston 45 is'actuatedoutwardly by the cam action. A coiled spring 63 contained in thevpiston chamber 3, engages the piston 45 to urge itj outwardly against the cam.

Also,- there is a passage 84 through the wall ton 4 is equipped with'a longitudinal rack surface I4 and there is a'sear segment 15 operatively inmesh'therewith. I r segment II is fixedly mounted on a transverse-shaft It extending rotatably through the housing walls and quipped at its outer end with a lever arm II to which a link, as'at 18, may be operatively attached for the control of some movable memher or instrumentality underthe control of the transmitter cylinder. The piston I, like piston 3, would be suitably packed to prevent leakage past its ends, and

also, the connections-of the cylinder with the pipes 5 and 8 would be as leak-tight as possible. At opposite ends of the cylinder, are valves IS-M9 that may be opened as is desirable in" charging the system and these are equipped with The housing la has been formed with a storage" chamber 52, and there is also a chamber 40 from which channels 80 and BI lead to the opposite ends of the cylinder for the automatic supplying of liquid to compensate for leakage should it occur. It will be explained that the channel 80 that leads to the left hand end of the cylinder as shown in Fig. 7 comprises a section that is formed horizontally in the central section la of the housing and a continuing part that is formed in the housing section lb. Thesechannels com.

mence with their respective endsof the cylinder through the valve equipped channels 21 and 33 the same as previously described in connection with the device of Fig. 2.

In the deviceas shown in Fig. '7, the pump cylinder and pump piston are arranged in a manner similar to those of the device previously described, except that the pump piston is equipped with valve devices whereby its operation under the influence of the cam 46 is to force the pressure medium from the chamber l2 into the chamber 40. Chamber I2 is equipped with a top connection with a source ll of supply of liquid medium, and there is a pressure relief valve 90 in the housing for relief of the medium from chamber 40 into the chamber l2.

It is anticipated also that the chamber 40 might be connected with the opposite ends of the cylinder I, through outside pipe connections instead of through the channels in the body of the structure if such is found more practical or desirable. In this way the difliculty of boring the connecting channels would be avoided. In the use of this device the functional operations of the shaft I3 actuate the cam 46 to efiect the pumping action of the pump piston, and this causes pressure to be built up in the chamber Ml which will be relieved at apre-determined point .by passage of the liquid medium back to the chamber I! through the pressure regulating valve.

In Fig. 8 we have shown a modified or alternative form of piston for use in the receiver for an automatic synchronization of the system should leakage occur past the piston or for other reasons. In this device the piston body is equipped with a longitudinal channel 9| extending from end to end and opening into the opposite ends of the enclosing cylinder. Mounted within the opposite ends of this channel are ball -inthe outlets and a loaded pressure relief valve check valves 94 and 95 that are yieldingly urged 1 to closed position by springs 96. Each valve is equipped with a stem 91 projecting beyond the corresponding end of the piston, and these stems are adapted should the piston be actuated beyond a pre-determined limit in either direction, to engage with the end wall of the cylinder thus to open the valve and permit flow of liquid past thevalve from the opposite end of the cylinder.

In this way farther travel of the piston is prevented, and automatic synchronization of the receiver pistonwith the transmitter piston is ac complished Within satisfactory limits.

Assuming the devices to be constructed as described, it is quite readily apparent that should leakage occur from the piping system or past the operating parts to any place that would afiect the timing or the positiveness of operation of the receiver cylinder with respect to movements of the transmitter piston, this leakage will be instantly and automatically compensated for by reason of the fact that such loss of pressure medium creates a condition of low pressure at the outgoing side of the valves in channels 21 and 33, and this permits flow of medium from cham-- ber H to compensate for the loss. With the understanding that pressurein chamber I2 is always relatively high, it can be understood that the system will always be charged under superatmospheric pressure, and, therefore, the disadvantages that heretofore have been experienced due to air pockets or vacuum pockets in the-piping system or in the cylinder is avoided.

It is quite readily apparent that details of construction other than herein shown might be em-, ployed in the arrangement of pumps and connecting passages, and still satisfactory results obtained. Therefore, it is not desired that the claims which terminate this specification should be confined to details of construction, but that they give an interpretation that is commensurate with the scope of the invention that is disclosed.

Having thus described my invention what I dehydraulic pressure medium filling the cylinder and conduit to be acted on by the piston, a shaft mounted for rotative motion and having an operating connection with the piston, a cam on the shaft, an auxiliary supply of hydraulic medium, a pump having an inlet to receive liquid from said supply and having an outlet communicating with the conduit system; said pump being operable by the action of the cam upon rotation of the shaft to cause delivery of medium from the auxiliary supply into the conduit system and a spring loaded pressure relief valve for the pump.

2. The combination with a closed hydraulic cyl inder-piston pulsator system of the character described and a shaft having a geared connection with the piston for its rotation in opposite directions in accordance with movement of the piston in opposite directions, of a pump, an auxiliary supply of hydraulic pressure medium for the pump, a cam on the shaft for actuation of the pump with each reciprocal movement of the piston, a pressure chamber having outlets to the opposite ends of the cylinder, back check valves m the pressurechdmbarn I.

3. In a closed hydraulic pulsator system of the character described, a double ended cylinder body, a doubled ended piston reciprocally containedtherein, fluid transmission conduits connected with opposite ends of the cylinder; said body comprising a closed liquid storage chamber in the body surrounding the medial portion of the piston; said chamber havin outlets to the opposite ends of the cylinder, back check valves in said outlets, an auxiliary supply of hydraulic pressure medium, a pump cylinder in the cylinder body, a pump piston operable therein concurrently with the piston movements, means for supplying liquid to the pump from said auxiliary supply for delivery thereby into said storage chamber to maintam a supply therein under super-atmospheric pressure, a pressure relief valve from the storage chamber, a shaft rotatably mounted in the cylinder body and having geared connection with the piston for rotation in Opposite directions in accordance with reciprocal action of the piston, and a cam fixed on the shaft and adapted to actuate the pump piston. I

4. In a closed hydraulic puisator system of the character described, a housing enclosing therein a double ended cylinder, a double ended piston v reciprocally fitted in the cylinder, and formed with a longitudinal gear rack, fluid transmission conduits [connected with the opposite ends of the cylinderQa shaft rotatably mounted in the housing transversely of the piston, a gear fixed on the shaft and in operative mesh with the ,gear rack,

a cam on the shaft, a pump cylinder mounted in v the housing, a pump piston disposed to engage the 

